Add support for LoadBalancing metrics

[axilleastr]

resolves: #51

Description

This PR enables support for CloudFlare LoadBalancer metrics. Introduces the following changes:

• feat: Export LoadBalancer analytics metrics

  This commit enables support for exporting LoadBalancer analytics metrics. LoadBalancer's pool health is reported:

  • 1 -> healthy
  • 0 -> unhealthy

  as long as the number of requests each pool receives from each CFL network location[1]

  1. https://developers.cloudflare.com/load-balancing/reference/load-balancing-analytics/#graphql-analytics

• feat: Export browser map page views count

  Export browser_map_page_views_count requests metric

Test plan

All changes have been tested locally with a local monitoring stack pulling metrics.

• LoadBalancers pool health:

• Browser map page views per family

[axilleastr]

@martinhaus for some reason I can't add reviewers, I would appreciate a review when you have some time :) Thanks in advance!

[martinhaus]

LGTM

thank you for the contribution @axilleastr !